The long-term goal of my laboratory is to elucidate the mechanisms that control the development of the neocortex and defects in this process that cause disease. We propose here to study the function of members of the cadherin superfamily in neocortical development. Our preliminary data show that several members of the cadherin superfamily are expressed in a spatio-temporal pattern consistent with a role in neocortical development. Our functional data provide evidence that cadherins have a role in regulating migration. Based on these findings, we hypothesize that several members of the cadherin superfamily cooperate to regulate cell migration during neocortical development. To test our hypothesis, we will: (i) Define the expression pattern and subcellular distribution of cadherin family members in the developing neocortex; (ii) Define the function of these cadherins for cell migration using both RNA interference and mouse genetics; (iii) define the cadherin ligand binding properties; (iv) identify the signaling pathways by which these cadherins regulate the motility of cortical neurons. We anticipate that our findings will demonstrate that cadherins are central for mediating cell-cell interactions during the formation of neocortical cell layers, and that their function is regulated by other molecules that have been implicated in neocortical development such as cdk5, doublecortin and reelin. As mutations and polymorphisms in human cadherin genes have been linked to epilepsy, mental retardation, Autism Spectrum Disorder and Alzheimer disease, we anticipate that our findings will be relevant to understanding disease mechanisms.